Flora of New Zealand Series

≡Parmelia xanthomelaena Müll.Arg., Flora 66: 48 (1883).

≡Pseudoparmelia xanthomelaena (Müll.Arg.) Hale, Phytologia 28: 191 (1974).

≡Paraparmelia xanthomelaena (Müll.Arg.) Elix & J. Johnst., Mycotaxon 27: 281 (1986).

Description : Thallus very tightly adnate to tightly adnate on rock, central parts appearing areolate, in distinctive rosettes, 4–5 cm diam., yellow-green to yellow-brown, darkening to deep olive-brown or blackish centrally. Lobes sublinear, 0.2–0.8 mm wide, irregularly dichotomously branching, ±contiguous and flattened at periphery, black-rimmed. Upper surface opaque, emaculate, without isidia or soredia, but developing tangential cracks in older lobes. Medulla white. Lower surface plane, black, glossy, sparsely to moderately rhizinate. Rhizines black, coarse, simple, 0.2–0.3 mm long. Apothecia markedly innate at first, 0.5–0.7 (–1.5) mm diam., disc brown to black; thalline exciple continuous. Ascospores 9–11 × 5–7μm. Pycnidia rare. Conidia cylindrical, 7–9 × 0.5 μm.

Chemistry : Cortex K−, UV−; medulla K+ yellow, C−, KC−, Pd+ yellow; containing usnic acid, stictic (major), constictic, ±norstictic, ±hypoconstictic and ±hypostictic acids.

S: Canterbury (Lake Tekapo), Otago (Ahuriri riverbed near Omarama, Galloway Station, Raggedy Ra., above Lake Onslow, Poolburn, Ida Valley). On vertical to steeply sloping, smooth faces of schist tors, on smooth, riverworn greywacke, and on prominent, white "sarsen stones", very difficult to remove from substratum. Associating with Acarospora spp., Caloplaca amylacea, Caloplaca sp., Candelariella vitellina, Lecanora dispersa, L. rupicola, Lecidella schistiseda, Xanthoparmelia spp., Rhizocarpon spp., Rinodina murrayi, Tephromela atra. Known also from alpine and subarid areas in Australia (Elix et al. 1986b; Elix 1994s: 306; McCarthy 2003c, 2006), from South Africa, Argentina, and Brazil (Hale 1990; Nash et al. 1995; Eliasaro & Adler 2002).

Palaeotropical

Illustrations : Elix et al. (1986b: 184, fig. 1 – as Xanthoparmelia adhaerens); Hale (1990: 225, fig. 74F); Elix 1994s: 200, fig. 92); Malcolm & Galloway (1997: 161).

Xanthoparmelia xanthomelaena is characterised by: the saxicolous habit; the small-foliose, crustose to subcrustose thallus with a black lower surface, very firmly attached to the substratum by sparse to moderately dense short rhizines; and innate, Aspicilia -like apothecia. The very closely attached thallus often forms convex areolae centrally, but lacks isidia and has metabolites of the stictic acid complex in the medulla. It was earlier referred to X. adhaerens (Nyl.) Hale (Elix et al. 1986b: 184–186), a South African species now referred to the genus Karoowia (Hale 1989), but which is not known from either Australia or New Zealand.